I enjoy making embroidered quilts and no longer use the 4x4 hoop, mostly the 5x7 and larger. I have a Brother 3000 with a sewing area of 7x11", and bought the 14"square hoop set-up from Hoop-it-all so I could embroider large blocks. It's really good as it can be turned to use all 4 sides, where most brands can only be used on 2 sides. Also, it doesn't have to be 'fixed' to the machine in the middle of the sides, (slides back and forwards) enabling sewing almost to the frame edge.
Recently bought a pre-loved Pfaff CV, and also got the larger square 'Grand' hoop for it. The large hoops are great for doing cushions and those big blocks, without having to re-hoop.
If you're looking at buying an embroidery machine, it will come with the necessary hoops, except for some specially purposed ones. So decide what you want to do with it beforehand, as many have been trading in the cheaper small machines for larger hooped ones.